Crystallization is the conversion of a substance or several substances from an amorphous solid, liquid, or gaseous state to the crystalline state. Generally, parameters such as crystal size distribution, median crystal size, crystal purity, and crystal shape are considered for crystals.
Crystallization of a molecule from a liquid can depend on the degree of saturation in the liquid as generated by cooling, evaporation, drowning out, or by a reaction. A liquid or a melt can be used for crystallizing materials.
A solution having a crystallized material capable of crystallization generally achieves a saturated concentration or supersaturated concentration for crystals to form or for existing crystals to grow. Crystals can grow from surfaces of containers or from seed crystals having irregular shapes or sizes. Crystals having undesirable variations in crystal size, and crystal size distribution are problematic, for example, in pharmaceutical formulations employing such crystals. There is a need for methods for forming crystals having controlled crystal sizes and crystal size distributions.